US20180345359A1

US20180345359A1 - Molding device for continuous casting equipped with agitator

Info

Publication number: US20180345359A1
Application number: US16/058,843
Authority: US
Inventors: Kenzo Takahashi
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-11-10
Filing date: 2018-08-08
Publication date: 2018-12-06
Also published as: US20150343523A1; JP5431438B2; CA2829183A1; CN103459064B; KR20130100210A; CA2829183C; EP2650063B1; KR101562876B1; AU2016201435B2; CN103459064A; EP2650063A4; AU2012337223B2; EP2650063A1; NZ612696A; AU2016201435A1; AU2012337223A1; WO2013069314A1; US20140069602A1; JP2013103229A

Abstract

There is provided a molding device for continuous casting equipped with an agitator that reduces the amount of generated heat, is easy to carry out maintenance, is inexpensive, and is easy to use in practice. The molding device for continuous casting equipped with an agitator of the invention receives liquid-phase melt of a conductive material, and a solid-phase cast product is taken out from the molding device through the cooling of the melt. The molding device includes a casting mold and an agitator provided so as to correspond to the casting mold. The casting mold includes a casting space that includes an inlet and an outlet at a central portion of a substantially cylindrical side wall, and a magnetic field generation device receiving chamber that is formed in the side wall and is positioned outside the casting space. The casting mold receives the liquid-phase melt from the inlet into the casting space and discharges the solid-phase cast product from the outlet through the cooling in the casting space. The agitator includes a magnetic field generation device having an electrode unit that includes first and second electrodes supplying current to at least the liquid-phase melt present in the casting space, and a permanent magnet that applies a magnetic field to the liquid-phase melt. The magnetic field generation device is received in the magnetic field generation device receiving chamber of the casting mold, generates magnetic lines of force toward a center in a lateral direction, makes the magnetic lines of force pass through a part of the side wall of the casting mold and reach the casting space, and applies lateral magnetic lines of force, which cross the current, to the melt.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No. 14/825,893, filed Aug. 13, 2015, which is a continuation of U.S. patent application Ser. No. 14/115,788, filed Nov. 5, 2013, which is a 371 of International Patent Application No. PCT/JP2012/052412, filed Feb. 2, 2012, which claims priority to Japanese Patent Application No. 2011-246668, filed Nov. 10, 2011. The entire contents of U.S. patent application Ser. Nos. 14/115,788 and 14/825,893 are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a molding device for continuous casting, which is equipped with an agitator, of continuous casting equipment that produces a billet, a slab or the like made of non-ferrous metal of a conductor (conductive body), such as Al, Cu, Zn, or an alloy of at least two of them, or an Mg alloy, or other metal.

BACKGROUND

In the past, a melt agitating method to be described below has been employed in a casting mold for continuous casting. That is, for the improvement of the quality of a slab, a billet, or the like, in a process for solidifying the melt, that is, when the melt passes through the casting mold, a moving magnetic field, which is generated from the outside of the casting mold by an electromagnetic coil, is applied to the melt present in the casting mold so that agitation occurs in the melt not yet solidified. A main object of this agitation is to degas the melt and to uniformize the structure. However, since the electromagnetic coil is disposed at the position close to high-temperature melt, the cooling of the electromagnetic coil and troublesome maintenance are needed and large power consumption is obviously needed. In addition, the generation of heat from the electromagnetic coil itself caused by the power consumption cannot be avoided, and this heat should be removed. For this reason, there are various problems in that the device itself cannot but become expensive, and the like.

CITATION LIST—PATENT LITERATURE

Patent Literature 1: JP 9-99344 A

SUMMARY

Technical Problem

The invention has been made to solve the above-mentioned problems, and an object of the invention is to provide a molding device for continuous casting equipped with an agitator that reduces the amount of generated heat, is easy to carry out maintenance, is inexpensive, and is easy to use in practice.
A molding device for continuous casting equipped with an agitator according to an embodiment of the present invention is a device which receives liquid-phase melt of a conductive material and from which a solid-phase cast product is taken out through the cooling of the melt. The molding device includes a casting mold including a casting space that includes an inlet and an outlet at a central portion of a substantially cylindrical side wall and a magnetic field generation device receiving chamber that is formed in the side wall and is positioned outside the casting space, the casting mold receiving the liquid-phase melt from the inlet into the casting space and discharging the solid-phase cast product from the outlet through the cooling in the casting space, and an agitator provided so as to correspond to the casting mold, the agitator including a magnetic field generation device having an electrode unit that includes first and second electrodes supplying current to at least the liquid-phase melt present in the casting space, and a permanent magnet that applies a magnetic field to the liquid-phase melt. The magnetic field generation device is received in the magnetic field generation device receiving chamber of the casting mold, generates magnetic lines of force toward a center in a lateral direction, makes the magnetic lines of force pass through a part of the side wall of the casting mold and reach the casting space, and applies lateral magnetic lines of force, which cross the current, to the melt.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(a) is a view illustrating the entire structure of an embodiment of the invention, and FIGS. 1(b) and 1(c) are explanatory views illustrating the operation thereof.

FIG. 2(a) is an explanatory plan view taken along line II(a)-II(a) of FIG. 1 and FIG. 2(b) is an explanatory view illustrating the bottom of an outer casting mold.

FIG. 3(a) is an explanatory plan view of a magnetic field generation device 31 of an agitator 3, and FIG. 3(b) is an explanatory plan view of a modified example thereof.

FIG. 4(a) is a plan view of another modified example of the magnetic field generation device 31 of the agitator 3, and FIG. 4(b) is an explanatory plan view of a modified example thereof.

FIG. 5 is a view illustrating the entire structure of another embodiment of the invention.

FIG. 6 is a view illustrating the entire structure of another embodiment of the invention.

FIG. 7 is a view illustrating the entire structure of still another embodiment of the invention.

FIG. 8(a) is a view illustrating the entire structure of yet another embodiment of the invention, FIG. 8(b) is a cross-sectional view taken along line VIII(b)-VIII(b) of FIG. 8(a), FIG. 8(c) is a cross-sectional view taken along line VIII(c)-VIII(c) of FIG. 8(a), FIG. 8(d) is an explanatory plan view of a magnetic field generation device, and FIG. 8(e) is an explanatory plan view of a lid.

FIG. 9(a) is a view illustrating the entire structure of still another embodiment of the invention, FIG. 9(b) is a cross-sectional view taken along line IX(b)-IX(b) of FIG. 9(a), and FIG. 9(c) is an explanatory plan view of a magnetic field generation device.

FIG. 10 is a view illustrating the entire structure of yet another embodiment of the invention.

DETAILED DESCRIPTION

For deeper understanding of an embodiment of the invention, an electromagnetic agitator, which uses electricity as power, of continuous casting equipment in the related art will be described briefly.
In the related art, a fixed amount of melt M of non-ferrous metal is discharged from a melt receiving box that is called a tundish and is poured into a casting mold that is provided on the lower side. Cooling water for cooling the casting mold is circulated in the casting mold. Accordingly, high-temperature melt starts to solidify from the outer periphery thereof (a portion thereof close to the casting mold) from the moment that the high-temperature melt comes into contact with the casting mold.
Since the melt, which is positioned at the central portion of the casting mold, is distant from the wall of the casting mold that is being cooled, the solidification of the melt positioned at the central portion of the casting mold is obviously later than that of the melt positioned at the peripheral portion of the casting mold. For this reason, two kinds of melt, that is, liquid (liquid-phase) melt and a solid (solid-phase) cast product are simultaneously present in the casting mold while being adjacent to each other with an interface interposed therebetween. Further, generally, if melt is solidified too rapidly, gas remains in the cast product (product) having been changed into a solid and causes the quality of the product to deteriorate. For this reason, degassing is facilitated by the agitating of the melt that is not yet solidified. The electromagnetic agitator, which uses electricity as power, has been used for the agitating in the related art.
However, when such an electromagnetic agitator is used, there are various difficulties as described above.
Accordingly, the invention is to provide a molding device for continuous casting equipped with an agitator that does not use the electromagnetic agitator using electricity as power and uses permanent magnets.
An embodiment of the invention will be described in more detail below.
The entire structure of an embodiment of the invention is illustrated in FIG. 1(a). FIG. 2(a) is an explanatory plan view taken along line II(a)-II(a) of FIG. 1(a), and mainly illustrates a part of an agitator 3 and a casting mold 2, and FIG. 3(a) is an explanatory plan view of the magnetic field generation device 31 of the agitator 3.
As understood from FIG. 1(a), a device according to an embodiment of the invention broadly includes a melt supply unit 1 that supplies melt M of non-ferrous metal of a conductor (conductive body), such as Al, Cu, Zn, or an ahoy of at least two of them, or an Mg alloy, or other metal; a casting mold 2 that receives the melt from the melt supply unit 1; and an agitator 3 that agitates the melt M present in the casting mold 2. A central portion of the casting mold 2 forms a so-called casting space 2A(1) that includes an inlet 2A(1)1 and an outlet 2A(1)2.
The melt supply unit 1 includes a tundish (melt receiving box) 1A that receives melt M from a ladle (not illustrated) or the like. The melt M is stored in the tundish (melt receiving box) 1A, inclusion is removed from the melt, and the melt M is supplied to the casting mold 2 from a lower opening 1B of the tundish at a constant supply rate. Only the tundish (melt receiving box) 1A is illustrated in FIG. 1.
The casting mold 2 is adapted in this embodiment so that a columnar product P (billet) is taken out from the casting mold. For this purpose, the casting mold 2 is formed so as to have a substantially cylindrical double structure (of which the cross-section has a ring shape). That is, the casting mold 2 includes an inner casting mold 21 and an outer casting mold 22 that are fitted to each other. The inner casting mold 21 is provided on the inside and made of a non-conductive material (non-conductive refractory material) such as graphite (carbon). The outer casting mold 22 is provided on the outside and made of a conductive material (conductive refractory material), such as aluminum or copper.
As described in detail below, the magnetic field generation device 31 is assembled so as to be received within the side wall of the outer casting mold 22. Meanwhile, since the technical idea is the same as described above even when a prismatic product (slab) is taken out, the technical idea of an embodiment to be described below can be applied as it is. Briefly, the shapes of components corresponding to a rectangular slab, which is a product, are merely changed.
The casting mold 2 further includes a water jacket 23 outside the outer casting mold 22.
The water jacket 23 is to cod the melt M that flows into the inner casting mold 21. That is, cooling water flows into the water jacket 23 from an inlet (not illustrated) and is circulated in the water jacket 23, the outer portion of the outer casting mold 22 is cooled by the cooling water, and the cooling water is discharged from an outlet (not illustrated). The melt M is rapidly cooled by the water jacket 23. Since water jackets having various known structures may be employed as the water jacket 23, the detailed description thereof will not be provided here.
In addition, a plurality of electrode insertion holes 2 a, 2 a, . . . into which electrodes 32A to be described below are inserted are formed at a predetermined interval on the circumference of the casting mold 2 having the above-mentioned structure. The electrode insertion holes 2 a are formed so as to be inclined downward toward the center of the casting mold 2. For this reason, if the surface of the melt M is lower than the upper openings of the electrode insertion holes 2 a even though the melt M is contained in the casting mold 2, there is no concern that the melt M will leak to the outside.
As described above, briefly, the agitator 3 is provided so as to be built in the side wall of the casting mold 2. The agitator 3 includes a permanent magnet type magnetic field generation device 31, and a pair of upper and lower electrodes (positive and negative electrodes) 32A and 32B.
In particular, as understood from FIG. 3(a), the magnetic field generation device 31 is formed in the shape of a ring (in a frame shape). The entire inner peripheral portion of the magnetic field generation device may be magnetized to an N pole, and the entire outer peripheral portion of the magnetic field generation device may be magnetized to an S pole. Further, four portions of the inner and outer peripheral portions may be partially magnetized to an N pole and an S pole as illustrated in, for example, FIG. 3(a), respectively.
As understood from the following description, the magnetic field generation device 31 does not necessarily need to be formed in the shape of a ring, and may be divided. That is, for example, as illustrated in FIG. 8(d), the cross-section of the magnetic field generation device may be formed of a plurality of arc-shaped permanent magnet pieces (FIG. 4). As briefly described above, particularly, as understood from FIG. 1(a), the magnetic field generation device 31 is assembled in the outer casting mold 22.
In more detail, as understood from FIG. 1(a), the outer casting mold 22 includes a magnetic field generation device receiving chamber 22 a which is formed in the side wall thereof and has a ring-shaped cross-section and of which a lower portion forms a release port. The magnetic field generation device receiving chamber 22 a is also understood from FIG. 2(b). FIG. 2(b) is a view of the outer casting mold 22 when the outer casting mold 22 is seen from below. In particular, as understood from FIG. 1(a), the magnetic field generation device 31 also having a ring-shaped cross-section is received in the magnetic field generation device receiving chamber 22 a, which has a ring-shaped cross-section and of which the lower portion is opened, from below so that the position of the magnetic field generation device in the vertical direction can be adjusted by movement. That is, the magnetic field generation device 31 is provided so that the height of the magnetic field generation device can be adjusted in the magnetic field generation device receiving chamber 22 a by desired units (not illustrated). Accordingly, it is possible to more efficiently agitate the melt M as described below by adjusting the height of the magnetic field generation device so as to correspond to liquid-phase melt M as understood from FIG. 1(a). The lower opening of the magnetic field generation device receiving chamber 22 a is closed by a ring-shaped lid 22B. The lid 22B may be formed so as to include discharge channels 22B(1) for discharging cooling water to the outside such as a lid 22B of FIG. 8(a) to be described below.
As described above, the four portions of the magnetic field generation device 31 are magnetized and form pairs of magnetic poles 31 a, 31 a, . . . as illustrated in FIG. 3(a). That is, a portion of each of the magnetic poles 31 a, 31 a facing the inside of the ring-shaped magnetic field generation device is magnetized to an N pole, and a portion thereof facing the outside of the ring-shaped magnetic field generation device is magnetized to an S pole. Accordingly, magnetic lines of force ML generated from the N pole horizontally pass through the melt M that is present in the casting mold 2.
The magnetization may be contrary to this. That is, the inner portions of all magnetic poles may be magnetized to a certain pole and the outer portions thereof may be magnetized to an opposite pole. One of additional characteristics of the invention is that a plurality of magnetic poles are disposed at a plurality of positions surrounding the melt M, which is not yet solidified, as understood from FIG. 3(a). Accordingly, it is possible to improve the quality of the product P by agitating all the melt M with an electromagnetic force that is generated according to Fleming's rule by magnetic lines of force and current as described below. Therefore, the number of the magnetic poles is four in FIG. 3(a), but is not limited to four and may be arbitrary. Further, as described above, the magnetic field generation device 31 does not need to be formed of a ring-shaped single body, and may be divided into a plurality of magnet bodies (magnet pieces), of which the number is arbitrary, as illustrated in FIG. 8(d).
In FIG. 1(a), current flows between the pair of electrodes 32A and 32B through the melt M and a cast product (product) P. One electrode 32A may be used, but a plurality of electrodes 32A may be used. In this embodiment, two electrodes 32A are used. The electrodes 32A are formed in the shape of a probe.
The respective electrodes 32A are inserted into the above-mentioned electrode insertion holes 2 a. That is, the electrodes 32A penetrate into the casting mold 2 (the inner casting mold 21 and the outer casting mold 22) from the water jacket 23. Inner ends of the electrodes 32A are exposed to the inside of the inner casting mold 21, come into contact with the melt M, and conduct electricity to the melt M. Outer ends of the electrodes 32A are exposed to the outside of the water jacket 23. The outer ends are connected to a power supply 34 that can supply variable direct current. The power supply 34 may have the function of an AC power supply as described below, and may have a function of changing frequency. The electrodes 32A may be supported above the upper opening of the casting mold 2 without penetrating the side wall of the casting mold 2 so that the inner ends of the electrodes 32A are inserted into the melt M from the surface of the melt M flowing into the casting mold 2. The electrodes 32A may be electrically connected to the inner casting mold 21 made of graphite or the like.
The number of electrodes used as the electrodes 32A may be arbitrary, and an arbitrary number of the electrodes 32A may be inserted into arbitrary electrode insertion holes of the electrode insertion holes 2 a, 2 a, . . . .
In FIG. 1(a), the lower electrode 328 is provided so that the position of the lower electrode 328 is fixed. The electrode 328 is formed of a roller type electrode. That is, the lower electrode 32B includes a rotatable roller 32Ba at the end thereof. The roller 32Ba comes into press contact with the outer surface of a columnar product P as a cast product (a billet or a slab) that is extruded in a solid phase state. Accordingly, as the product P extends downward, the roller 32Ba is rotated. That is, when the product P is extruded downward, the product P extends downward in FIG. 1 while coming into contact with the roller 32Ba and rotating the roller 32Ba.
Accordingly, when a voltage is applied between the pair of electrodes 32A and 32B from the power supply 34, current flows between the pair of electrodes 32A and 32B through the melt M and the product P. As described above, the power supply 34 is adapted so as to be capable of controlling the amount of current flowing between the pair of electrodes 32A and 32B. Therefore, it is possible to select current where the liquid-phase melt M can be agitated most efficiently in a relationship with the magnetic lines of force ML.
Next, the operation of the device having the above-mentioned structure will be described.
In FIG. 1(a), a fixed amount of the melt M, which is discharged from the tundish (melt receiving box) 1A, is input to the upper portion of the casting mold 2. The casting mold 2 is cooled through the circulation of water in the water jacket 23, so that the melt M present in the casting mold 2 is rapidly cooled and solidified. However, the melt M present in the casting mold 2 has a two-phase structure where the upper portion of the melt is liquid (liquid phase), the lower portion thereof is solid (solid phase), and the upper and lower portions of the melt are adjacent to each other at an interface ITO. When passing through the casting mold 2, the melt M is formed in the shape (a columnar shape in this embodiment) corresponding to the shape of the casting mold. Accordingly, a product P as a slab or billet is continuously formed.
Further, since the permanent magnet type magnetic field generation device 31 is received in the side wall of the casting mold 2 as understood from FIG. 1(a) and the like, the magnetic field (magnetic lines of force ML) of the magnetic field generation device reaches the melt M, which is present in the casting mold 2 in the lateral direction. In this state, when direct current is supplied to the lower electrode 32B from the upper electrodes 32A by the power supply 34, the current flows to the lower electrode 32B from the upper electrodes 32A through the melt (liquid phase) M of aluminum or the like and the product (solid phase) P. At this time, the current crosses the magnetic lines of force ML, which are generated from the permanent magnet type magnetic field generation device 31, substantially at right angles to the magnetic lines of force. Accordingly, rotation occurs in the liquid-phase melt M in accordance with Fleming's left-hand rule. The melt M is agitated in this way, so that impurities, gas, and the like contained in the melt M float and so-called degassing is actively performed. Accordingly, the quality of the product a slab or a billet) P is improved.
Now, cooling capacity is increased or reduced by the water jacket 23 or the like, the solidification rate of the melt M is changed and the interface IT0 between the melt (liquid-phase) M and a product (solid-phase) P moves up and down according to this. That is, when cooling capacity is increased, the interface IT0 moves up like an interface IT1 as illustrated in FIG. 1(b). When cooling capacity is reduced, the interface IT0 moves down like an interface IT2 as illustrated in FIG. 1(c). Further, it is preferable that the magnetic field generation device 31 be moved up and down according to the positions of the interfaces IT0, IT1, and IT2 in order to efficiently agitate the melt M. Accordingly, it is possible to obtain a product P as a high-quality product by reliably and efficiently agitating the melt M. For this purpose, the magnetic field generation device is adapted so that the height of the magnetic field generation device 31 can be adjusted in the vertical direction according to the heights of these interfaces IT1 and IT2 as illustrated in FIGS. 1(b) and 1(c) and the position of the magnetic field generation device 31 can be kept. Accordingly, it is possible to efficiently agitate the melt M as described above.
On the contrary, the double structure of the casting mold 2 may be formed so that the inner portion of the casting mold is made of a conductive material and the outer portion thereof is made of a non-conductive material. In this case, at least the electrodes 32A may come into electronically contact with the conductive material that forms the inner portion of the casting mold. Even in this case, a magnetic field generation device receiving chamber 22 a may be formed in an outer member.
Further, the casting mold 2 may have not a double structure but a single structure. In this case, the casting mold 2 may be made of only a conductive material, and the electrodes 32A may conduct electricity to the casting mold 2. The structure of the other electrode 32B may be the same as described above.
On the contrary, the casting mold 2 may be made of only a non-conductive material. In this case, it is necessary to make the electrodes 32A conduct electricity to the melt M present in the casting mold 2 by making the electrodes 32A penetrate into the casting mold 2 as illustrated in FIG. 1(a).
In these cases, obviously, a magnetic field generation device receiving chamber 22 a may be formed in a member having a single structure.
A magnetic field generation device 31A of FIG. 3(b) may be used instead of magnetic field generation device 31 of FIG. 3(a). The magnetization direction of the magnetic field generation device 31A of FIG. 3(a) is opposite to that of the magnetic field generation device 31 of FIG. 3(b). Both the magnetic field generation devices have the same function.
Further, magnetic field generation devices 31-2 and 31A-2 of FIGS. 4(a) and 4(b) may be used instead of the magnetic field generation devices 31 and 31A of FIGS. 3(a) and 3(b). The magnetic field generation devices 31-2 and 31A-2 of FIGS. 4(a) and 4(b) are adapted so that a plurality of rod-like permanent magnets PM are fixed to the inside of a ring-shaped support (yoke) SP. These have the same function
Furthermore, an electrode, which includes the roller 32Ba at the end thereof, has been described as the lower electrode 32B in the above-mentioned embodiment. However, the lower electrode does not need to necessarily include the roller 32Ba. Even though a product P is continuously extruded, the electrode 32B only has to conduct electricity to the product P and may employ various structures. For example, an elastic member having a predetermined length is used as the electrode 32B and is bent, for example, so as to be convex upward or downward in FIG. 1, and the end of the elastic member comes into press contact with the cast product P by the force of restitution. In this state, the cast product P may be allowed to extend downward.
According to the above-mentioned embodiment of the invention, it is possible to obtain the following effects.
In the embodiment of the invention, melt M that is not yet solidified is agitated to give movement, vibration, and the like to the melt M, so that a degassing effect and the uniformization and refinement of the structure are achieved.
In more detail, since the magnetic field generation device 31 is adapted so as to be capable of being adjusted in the vertical direction in the embodiment of the invention, it is possible to obtain a high-quality product P by reliably agitating the melt M. This is one of the characteristics of the invention as described above, and an idea, in which a magnetic field generation device 31 provided outside the casting mold is moved up and down in a device that is rapt to be high temperature and large in size and hardly has an empty space as in the embodiment of the invention, itself is an idea that is not accustomed to those skilled in the art. Accordingly, a technique of the invention, in which a magnetic field generation device is received in a casting mold and can be adjusted in the vertical direction, is a technical idea that is peculiar to the inventor.
Further, since the magnetic field generation device 31 is formed in the embodiment of the invention so that a plurality of magnetic poles are disposed at the positions surrounding the melt M or a ring-shaped magnet surrounding the melt M is disposed, it is possible to efficiently agitate all the melt M with an electromagnetic force that is generated according to Fleming's rule by magnetic lines of force and current. Accordingly, it is possible to obtain a product P as a high-quality product. That is, in the embodiment of the invention, it is possible to efficiently agitate the melt M by making the best use of an electromagnetic force that is generated according to Fleming's rule. In addition, the axis of the rotation of the melt M, which is caused by this agitating of the melt, is an axis parallel to the center axis of the product P in FIG. 1(a). Accordingly, it is possible to obtain a high-quality product as a product P by making the rotational drive of the melt M reliable.
Moreover, in the embodiment of the invention, melt M is agitated with an electromagnetic force that is generated according to Fleming's rule and is agitated by the cooperation between small current flowing in the melt M and a magnetic field generated from the magnetic field generation device 31. Accordingly, it is possible to obtain a device that stably and continuously expects reliable agitation unlike melting and agitation performed using the intermittent flow of large current according to the principle of arc welding or the like and has low noise and high durability.
It is obvious that the above-mentioned effects are obtained from all embodiments to be described below.
Meanwhile, direct current has been supplied between the electrodes 32A and 32B in the above description, but alternate current having a low frequency of about 1 to 5 Hz may be supplied from the power supply 34. In this case, the melt M does not rotate but repeatedly vibrates according to the cycle thereof in the relationship with a magnetic field that is generated from the magnetic field generation device 31. Impurities are removed from the melt M even by the vibration. This modified example may be applied to all embodiments to be described below. In this case, it is obvious that a power supply having a function of changing frequency is employed as the power supply 34.
Further, the realization of mass production facilities is currently required in the industry. It is essential to realize a casting mold that is as small as possible when mass production is considered.
Here, the electromagnetic agitating device in the related art can cope with a case where several slabs or billets are produced at one time. However, at present, there is a demand for the production of billets of which the number exceeds 100. The electromagnetic agitator in the related art cannot cope with this demand.
However, permanent magnets are used as the magnetic field generation device in the device of the invention. For this reason, it is possible to make the device very compact in comparison with the electromagnetic agitator that is supplied with large current. Accordingly, it is possible to sufficiently realize a molding device for a mass production facility. Further, since the magnetic field generation device is permanent magnet type, it is possible to obtain a device having effects, such as no heat generation, power saving, energy saving, and less maintenance, as a magnetic field generation device.
FIG. 5 illustrates another embodiment of the invention.
More current is supplied to this liquid-phase melt M to generate a larger electromagnetic force so that the melt M is rotationally driven.
This embodiment is different from the embodiment of FIG. 1(a) in the structure of a casting mold 2A. Other structures are substantially the same as FIG. 1(a). Accordingly, the detailed description thereof will not be repeated here.
That is, the casting mold 2A of this embodiment includes a substantially cylindrical casting mold body 2A1. The casting mold body 2A1 includes a circumferential groove 2A1(a) that is formed on the inner peripheral surface thereof. An insulating film 2A2 is formed on the inner surface (the peripheral surface and the bottoms) of this groove, and an embedded layer 2A3 is formed by embedding the same conductive material as the casting mold body 2A1 on the insulating film 2A2. An insulating layer portion is formed of the insulating film 2A2 and the embedded layer 2A3. The insulating layer portion is formed on a part of the inner surface of the casting mold, and functions as a portion that does not allow the flow of current from the casting mold.
This insulating layer portion is formed on a slightly lower portion of the inner surface of the casting mold body 2A1.
Accordingly, current is hardly allowed to flow to the cast product P from the insulating layer portion of the casting mold body 2A1, that is, a portion adjacent to the cast product P.
In addition, a terminal 2A4 is provided on the outer periphery of the casting mold body 2A1. Power can be supplied to the casting mold 2A from the power supply 34 through this terminal 2A4.
When a voltage is applied between the terminal 2A4 and the electrode 32B by the power supply 34 in the device having this structure, current flows in the casting mold body 2A1, the melt M, and the cast product P. Since current does not flow in the insulating film 2A2 and the embedded layer 2A3 at this time, larger current flows in the melt M. Accordingly, a larger electromagnetic force, which allows the melt M to be agitated, is obtained.
FIG. 6 illustrates still another embodiment.
This embodiment is a modification of the embodiment of FIG. 1(a).
This embodiment is different from the embodiment of FIG. 1(a) in the disposition of the upper electrodes 32A of FIG. 1(a). That is, in this embodiment, one electrode 32A0 is disposed or a plurality of electrodes 32A0 are disposed annularly, these electrodes 32A0 are supported by arbitrary units other than the casting mold 2A and the like (the casting mold 2A and the water jacket 23), and a lower end portion of each of the electrodes 32A0 is inserted into the melt M. Accordingly, it is possible to adjust the length of the lower end portion, which is inserted into the melt M, of the electrode 32A0 with large degree of freedom regardless of the casting mold 2A and the like. Moreover, obviously, a normal mold may be used as the casting mold 2A or the like, and electrode insertion holes 2 a for electrodes 32A1 do not need to be formed in the casting mold 2A or the like. Therefore, it is also possible to prevent the increase in the manufacturing costs of these.
Other structures are the same as the embodiment of FIG. 1(a).
FIG. 7 illustrates yet another embodiment.
This embodiment may be regarded as a modified example of the embodiment of FIG. 6.
The embodiment of FIG. 7 is assumed as a device that can be operated when melt M is poured into a casting mold 2A, which is provided on the lower side, from a tundish (melt receiving box) 1A, which is provided on the upper side, as continuous melt with no interruption. That is, it is assumed that the melt M present in the tundish (melt receiving box) 1A and the melt M present in the casting mold 2A are integrally connected to each other.
In FIG. 6, the electrodes 32A0 are inserted into the melt M present in the casting mold 2. However, in FIG. 7, an electrode 32A1 is supported by arbitrary units so as to be inserted into the melt M present in the tundish (melt receiving box) 1A on the premise of the above-mentioned case. Accordingly, it is possible to obtain the same advantage as the above-mentioned embodiment of FIG. 6. In addition, it is possible to set and adjust a distance between the tundish (melt receiving box) 1A and the casting mold 2A or the like regardless of the electrode 32A1.
Other structures are substantially the same as FIG. 6.
FIGS. 8(a) to 8(d), FIGS. 9(a) to 9(c), and FIG. 10 illustrate other embodiments of the invention, respectively.
The same members of these embodiments as the members of the above-mentioned embodiment are denoted by the same reference numerals and the description thereof will not be repeated.
In these embodiments, a water jacket for cooling does not need to be separately provided, a water flow chamber 22 a(2), which functions as both a cooling chamber and a magnetic field generation device receiving chamber, is formed in the side wall of a casting mold 2, that is, the side wall of the outer casting mold 22, and a magnetic field generation device 31 as a permanent magnet is received in the water flow chamber 22 a(2) so that the position of the magnetic field generation device can be adjusted in the vertical direction.
Meanwhile, a magnetic field generation device receiving space (magnetic field generation device receiving chamber) 22 a(2) illustrated in FIG. 8(c) may be divided so as to receive a plurality of permanent magnet pieces 31A, which are illustrated in FIG. 8(d) and disposed at a predetermined interval, respectively. For example, the magnetic field generation device receiving space may be formed of a plurality of partial magnetic field generation device receiving chambers having an arc-shaped cross-section.
First, a device of manufacturing a billet of the embodiment illustrated in FIGS. 8(a) to 8(e) will be described.
That is, as understood from FIG. 8(a), the outer casting mold 22 includes a water flow chamber 22 a(2) that is opened downward and has a ring-shaped cross-section, and the water flow chamber 22 a(2) is hermetically-sealed by a lid 22B(1). FIG. 8(b) is a view illustrating the inner casting mold 21 and the outer casting mold 22 taken along line VIII(b)-VIII(b) from below when the lid 22B(1) is removed. This lid 22B(1) forms a part of the casting mold 2.
As understood from FIG. 8(a), a magnetic field generation device 31, which is formed of a plurality of permanent magnet pieces 31A (FIG. 8(c)) having an arc-shaped cross-section, is received in the ring-shaped water flow chamber 22 a(2) serving as a magnetic field generation device receiving space (receiving chamber) so as to be capable of being adjusted in the vertical direction. That is, the water flow chamber (cooling chamber) 22 a(2) functions as both a cooling water flow chamber and a magnetic field generation device receiving chamber. A plan view of these permanent magnet pieces 31A is illustrated in FIG. 8(d). The inner portion of each of the permanent magnet pieces 31A is magnetized to an N pole and the outer portion thereof is magnetized to an S pole. The magnetization may be contrary to this. That is, the magnetic field generation device 31 is provided so that the height of the magnetic field generation device can be adjusted in the water flow chamber 22 a(2) by arbitrary units (not illustrated). Accordingly, it is possible to more efficiently agitate the melt M by adjusting the height of the magnetic field generation device so as to correspond to liquid-phase melt M as described above.
The lower opening of the water flow chamber 22 a(2) is dosed by the above-mentioned ring-shaped lid 22B. A plan view of the lid 22B is illustrated in FIG. 8(e). As understood from FIGS. 8(e) and 8(a), a plurality of discharge channels 22B(1) for cooling water are formed in the lid 22B(1). As understood from FIGS. 8(a) and 8(e), the plurality of discharge channels 22B(1) include a plurality of inlets 22B(1)a 1 that are opened to the upper surface of the lid 22B, and include outlets 22B(1)a 2 on the peripheral surface of the lid 22B. Accordingly, coding water present in the water flow chamber 22 a(2) enters from the plurality of inlets 22B(1)a 1, flows out of the outlets 22B(1)a 2, and is jetted to the outer periphery of the product P to cod the product P. That is, cooling water enters the water flow chamber 22 a(2) from inlets (not illustrated), is circulated in the water flow chamber while cooling the product, and is discharged while being jetted to the outside from the discharge channels 22B(1).
Since the operation of the above-mentioned device of FIGS. 8(a) to 8(e) is the same as that of the above-mentioned embodiment, the description thereof will not be repeated.
Meanwhile, the magnetic field generation device 31 has been formed of the plurality of permanent magnet pieces 31A in the above-mentioned embodiment of FIGS. 8(a) to 8(e). However, it is obvious that the magnetic field generation device may be integrally formed as in FIG. 3(a). Further, the water flow chamber 22 a(2) serving as the magnetic field generation device receiving space is formed in a circumferential shape as understood from FIG. 8(b). However, the water flow chamber is not limited to this shape, and may be formed of a plurality of cell chambers that are divided in the circumferential direction and have an arc-shaped cross-section. It is preferable that cooling water can flow in each cell chamber and the permanent magnet piece 31A be received in each cell chamber so as to be capable of moving up and down.
In the device of FIGS. 8(a) to 8(e), the magnetic field generation device 31 is not provided outside the casting mold 2, and a cavity (water flow chamber 22 a(2)) is formed in the casting mold 2 (outer casting mold 22) and the magnetic field generation device 31 is received in the cavity. Accordingly, it is possible to obtain the following characteristics.
A permanent magnet, which is small and has a small capacity, may be used as the magnetic field generation device 31.
That is, if the magnetic field generation device 31 is provided outside the casting mold, it is inevitable that a distance between the magnetic field generation device 31 and the melt M is slightly increased. However, since the magnetic field generation device is built in the casting mold 2 in this embodiment, the distance between the magnetic field generation device 31 and the melt M is reduced. Accordingly, a permanent magnet, which is small and has a small capacity, may be used to obtain the same agitating performance.
It is possible to significantly improve a working property.
That is, when this device is operated, a plurality of inspectors should be positioned around the device to perform various kinds of measurement, nondestructive inspection, and the like and should perform such the measurement and the like for the check of a product P. However, in the case of the magnetic field generation device that is provided outside, the increase in size and volume cannot be avoided and it cannot be denied that it is difficult to perform such the measurement since a strong magnetic field is generated. However, since the magnetic field generation device 31 is provided in the casting mold 2 in this embodiment, a volume is not increased and the intensity of a magnetic field emitted to the outside is reduced. For this reason, it is easy to perform various kinds of measurement and the like.
It is possible to significantly improve productivity.
That is, it is possible to reduce time required for the above-mentioned measurement and the like. As a result, it is possible to increase the manufacturing rate of a product P per unit time.
It is possible to reduce size.
That is, since the magnetic field generation device 31 is a built-in type, it is possible to provide a device that is small as a whole as much as that.
It is possible to save a space of an installation location.
That is, since the magnetic field generation device 31 is a built-in type when the device is regarded as a device manufacturing the same product P although being the same as described above, the size of the device is reduced as a whole. Accordingly, it is possible to install the device even at a narrow place. As a result, flexibility is obtained in the usefulness of the device.
The above-mentioned effects will be described below from a different standpoint.
When a product P is manufactured by this device, for example, five or six workers gather around the device and should perform high-density works (works for monitoring and preventing the leakage of melt, works for monitoring and preventing the jet of melt, and the like) in a short time. When these works are performed by a plurality of workers, a working property is good in the built-in type device of this embodiment as compared to a case where the magnetic field generation device 31 is provided outside so as to protrude. That is, since the external appearance of the device has the same dimensions as the dimensions of a device that does not include the magnetic field generation device 31 that is a device in the related art, the device of this embodiment is very easy to use at the work site.
Further, it is preferable that the magnetic field generation device 31 be close to the melt M as much as possible in order to reliably apply a magnetic field to the melt M, and this is realized in a built-in type.
When the magnetic field generation device 31 is provided outside, the influence of a magnetic field on various measuring instruments such as temperature sensors should be considered. However, since the influence thereof is reduced in a built-in type, a built-in type is more advantageous in measurement. That is, when a product P, such as a slab or a billet, is manufactured, the measurement, management, and the like of temperature in several positions are very important to maintain the quality of a product. This embodiment is very advantageous in the measurement of temperature and the like.
If a built-in type magnetic field generation device as in this embodiment is used instead of the magnetic field generation device provided outside, the size, weight, and volume of a device may be reduced when the same magnetic field is applied to the melt M. Accordingly, the device is easy to use. That is, since the respective components of this device are consumables, the respective components of this device need to be replaced whenever a predetermined operation time has passed. However, since the magnetic field generation device 31 is small and light, a work for replacing the magnetic field generation device and the like are very easily performed.
Since a work at the device of this embodiment is a work that is performed at a so-called high temperature of about 700° C., the work is very dangerous for a worker. However, a magnetic field generation device, which is small and of which the intensity of a magnetic field is low, may be used as the magnetic field generation device 31. Further, a tool, which is used for the adjustment, maintenance, and the like of the device, is generally a ferromagnetic body made of iron and safety shoes and the like are also made of iron. However, if a magnetic field of the magnetic field generation device 31, which is emitted by the outside, is reduced a little, the safety of a security officer, a worker, a measuring person, and the like is ensured.
It is obvious that the effects described above with reference to FIGS. 8(a) to 8(e) are mentioned in not only the device of FIG. 1 and the like but also devices for manufacturing a slab that are to be described below and illustrated in FIGS. 9(a) to 9(c) and 10.
FIGS. 9(a) to 9(c) illustrate a device for manufacturing a slab. However, the basic technical idea of the device is the same as described above except that a billet has a circular shape and a slab has a rectangular shape. Accordingly, the same members are denoted by the same reference numerals and the description thereof will not be repeated.
A difference will be described below.
The weight of a slab as a product P is very heavy. For this reason, a billet can be pulled in the horizontal direction, but a slab as a product P is not obtained unless taken out in the vertical direction. For this reason, a pedestal 51 is prepared, and a product P is taken out while riding the pedestal 51 and being gradually pulled downward. A lower electrode 32B is embedded in the pedestal 51. A magnetic field generation device 31 is illustrated in FIGS. 9(b) and 9(c). FIG. 9(b) is a cross-sectional view taken along line IX(b)-IX(b) of FIG. 9(a), and FIG. 9(c) is a plan view of the magnetic field generation device 31. Here, the magnetic field generation device 31 uses four permanent magnet pieces 31A and forms two pairs facing each other, but may use any one pair.
FIG. 10 illustrates a modified example of FIG. 9(a).
In FIG. 10, a pair of electrodes 32A and 32B is used while being inserted into melt M. The inventor confirmed by an experiment that the melt M is agitated even though the electrodes 32A and 32B are used in this way. That is, even though the pair of electrodes 32A and 32B is employed as illustrated in FIG. 10, the magnetic lines of force generated from a magnetic field generation device 31 and current flowing between the pair of electrodes 32A and 32B flow in various paths in the melt M and generate an electromagnetic force according to Fleming's rule.

Claims

I/We claim:

1. A method for casting nonferrous metal, the method comprising:

shaping nonferrous metal by moving the nonferrous metal through a casting mold in a casting direction;

passing electrical current between a first electrode electrically connected to the shaped nonferrous metal at a first location and a second electrode electrically connected to the shaped nonferrous metal at a second location spaced apart from the first location; and

applying a magnetic field to a portion of the shaped nonferrous metal between the first location and the second location, wherein passing the electrical current and applying the magnetic field together agitate the portion of the shaped nonferrous metal between the first location and the second location.

2. The method of claim 1 wherein:

passing the electrical current includes passing direct current; and

passing the electrical current and applying the magnetic field together agitate the portion of the shaped nonferrous metal between the first location and the second location by causing the portion of the shaped nonferrous metal between the first location and the second location to rotate about an axis parallel to the casting direction.

3. The method of claim 1 wherein:

passing the electrical current includes passing alternating current; and

passing the electrical current and applying the magnetic field together agitate the portion of the shaped nonferrous metal between the first location and the second location by causing the portion of the shaped nonferrous metal between the first location and the second location to vibrate.

4. The method of claim 1 wherein the second location is spaced apart from the first location in the casting direction.

5. The method of claim 1 wherein applying the magnetic field includes applying the magnetic field via one or more permanent magnets.

6. The method of claim 5 wherein applying the magnetic field includes applying the magnetic field while the one or more permanent magnets are stationary.

7. The method of claim 5 wherein:

the casting mold defines a casting space having a round cross-sectional shape in a plane perpendicular to the casting direction;

the one or more permanent magnets are disposed around the shaped nonferrous metal in a plane perpendicular to the casting direction; and

applying the magnetic field includes applying the magnetic field via one or more curved faces of the one or more permanent magnets.

8. The method of claim 5 wherein:

the casting mold defines a casting space having a rectangular cross-sectional shape in a plane perpendicular to the casting direction;

applying the magnetic field includes applying the magnetic field via one or more straight faces of the one or more permanent magnets.

9. The method of claim 5, further comprising adjusting a position of the one or more permanent magnets in the casting direction relative to the casting mold.

10. The method of claim 1 wherein applying the magnetic field includes applying the magnetic field such that the same poles horizontally oppose one another via the shaped nonferrous metal.

11. The method of claim 1 wherein applying the magnetic field includes applying the magnetic field such that field lines of the magnetic field cross the electrical current at right angles.

12. A casting system, comprising:

a casting mold configured to continuously shape nonferrous metal moving through the casting mold in a casting direction;

a first electrode positioned to be electrically connected to the shaped nonferrous metal at a first location;

a second electrode positioned to be electrically connected to the shaped nonferrous metal at a second location spaced apart from the first location;

a power supply configured to pass electrical current through a portion of the shaped nonferrous metal between the first location and the second location via the first electrode and the second electrode; and

a magnetic field generation device configured to apply a magnetic field to the portion of the shaped nonferrous metal between the first location and the second location.

13. The casting system of claim 12 wherein:

the power supply is configured to pass direct current through the portion of the shaped nonferrous metal between the first location and the second location via the first electrode and the second electrode; and

the power supply and the magnetic field generation device are collectively configured to agitate the portion of the shaped nonferrous metal between the first location and the second location by causing the portion of the shaped nonferrous metal between the first location and the second location to rotate about an axis parallel to the casting direction.

14. The casting system of claim 12 wherein:

the power supply is configured to pass alternating current through the portion of the shaped nonferrous metal between the first location and the second location via the first electrode and the second electrode; and

the power supply and the magnetic field generation device are collectively configured to agitate the portion of the shaped nonferrous metal between the first location and the second location by causing the portion of the shaped nonferrous metal between the first location and the second location to vibrate.

15. The casting system of claim 12 wherein the magnetic field generation device includes one or more permanent magnets though which the magnetic field generation device is configured to apply the magnetic field to the portion of the shaped nonferrous metal between the first location and the second location.

16. The casting system of claim 15 wherein:

the one or more permanent magnets are positioned to be disposed around the shaped nonferrous metal in a plane perpendicular to the casting direction; and

the one or more permanent magnets include one or more curved faces through which the magnetic field generation device is configured to apply the magnetic field to the portion of the shaped nonferrous metal between the first location and the second location.

17. The casting system of claim 15 wherein:

the one or more permanent magnets include one or more straight faces through which the magnetic field generation device is configured to apply the magnetic field to the portion of the shaped nonferrous metal between the first location and the second location.

18. The casting system of claim 15 wherein:

an inner side of the one or more permanent magnets is magnetized to one of N and S poles; and

an outer side of the one or more permanent magnets is magnetized to the other of N and S poles such that the same poles horizontally oppose one another via the shaped nonferrous metal.

19. The casting system of claim 15 wherein the one or more permanent magnets are adjustably mounted to the casting mold such that a position of the one or more permanent magnets in the casting direction can be adjusted relative to the casting mold.

20. The casting system of claim 15 wherein:

the casting mold includes a water jacket; and

the one or more permanent magnets are disposed within the water jacket.